1. Field of Invention
The present invention relates to a computer switching device. More particularly, the present invention relates to a KVM switch and a method for multiple chaining and providing high quality transmissions of analog signals.
2. Description of Related Art
With the rapid development of information technology, computers and their peripherals have become very popular. Computer users often use mice and keyboards to control their computers. Through the use of monitors or speakers, computer users can monitor the state of their computers. Sometimes a user may have more than one computer to process different types of data. Traditionally, each computer is equipped with one set of input/output (IO) peripheral devices, including the keyboard, mouse, monitor, and speakers. However, this is a waste of money and space if one has several computers.
In contrast, large business or enterprise internal networks often involve tens to thousands of servers. Each server needs a monitor, a keyboard, and a mouse for management. In practice, one rarely needs to manipulate these devices. Most of the time, the servers do not need to be controlled by the manager. In this situation, it is costly and a waste of space to have a set of IO peripheral devices for each server.
Therefore, a keyboard video mouse (KVM) switch is proposed to use at least one set of operation devices to manage several computers. Using the KVM switch does not only solve the cost problem, it simultaneously solves the problems of equipment and space. It may also conquer the compatibility problem among different interfaces.
However, the quantities of computers and sets of operating devices, which are available to be connected to the KVM switch, are restricted by the limitations of hardware design and cost of the KVM switch. Moreover, the conventional KVM switches are difficult to connect to one another, and when multiple sets of operating devices manage multiple computers at the same time, the analog signals transmitted therebetween, such as video signals, do not easily achieve their connections and switches in the system.
The foregoing two disadvantages inconvenience users in practical use. Prior art cannot provide a high-quality transmission for analog signals between multiple sets of operating devices and multiple computers and also cannot achieve the connections and switches in parallel of the analog signals. Especially for large-scale system providers or middle and small-scale internal networks, if the KVM switches cannot simultaneously handle the computers and the sets of operating devices in great quantities, the costs of system settings and maintenance are raised, and the transmission performance of the whole system is reduced.